Two aspects are key when optimising a maritime transport system; the design of the transport system and the design of the ships. Studies indicate that more than half of the energy efficiency savings potential is associated with the transport system. Decisions related to routes, fleet composition, ship capacities and speed highly influence the fuel consumption relative to the transport work carried out. Developing a realistic operating profile true to real-life operation will ensure that the vessel design may be matched to actual needs and running conditions, thus producing a more energy efficient vessel. Operating profiles will vary with the trading route and should thus be carefully fitted to the vessel type under consideration.
The most effective measures for reducing energy consumption can be taken in the concept phase of the vessel. These are primarily the choice of the main dimensions and the adoption of the general arrangement, the definition of the propulsor and the definition of a suitable operational profile. Further savings can be achieved during the design phase of the ship by implementing an effective and optimised lines design. Holistic approaches combine parametric modelling of the hull form, advanced computational fluid dynamics (CFD) and genetic optimisation strategies. The right decision is strongly driven by the intended operational profile of the vessel and the grade of flexibility allowed.
The fuel savings that can often be made by optimising the operation of engine and machinery systems originate from two main causes; (a) the crew’s traditional way of operating the systems being suboptimal, and (b) the systems installed in older ships are not up-to-date or either tuned for optimal operation or the ship’s current operational profile. In a strategy to improve fuel efficiency for machinery and systems, useful experience can be gained by using the information available from the on-board power management system coupled with advanced modelling and simulation using in-house developed computer tools.